linux 产生随机数和字符串的方法

参考51CTO博客作者long9617的原创作品
https://blog.51cto.com/longlei

1、$RANDOM

[root@fan ~]# echo $RANDOM
28679
[root@fan ~]# echo $RANDOM
6675
[root@fan ~]# echo $RANDOM
177

获取8位随机字符和数字

[root@fan ~]# echo $RANDOM |md5sum |cut -c 1-8
f890d6d1
[root@fan ~]# echo $RANDOM |cksum |cut -c 1-8 
30180605

2、openssl

openssl rand 用于产生指定长度个bytes的随机字符
-base64 / -hex 对随机字符串进行base64编码或用hex格式显示

[root@fan ~]# openssl rand -base64 5
zBGxHQs=
[root@fan ~]# openssl rand -base64 4
h3T2OQ==
[root@fan ~]# openssl rand -base64 8
hRD42l4L2bQ=
[root@fan ~]# openssl rand -base64 10
azR7c+a6JR/vmg==
[root@fan ~]# openssl rand -base64 10
IxlqRmi0P70E/g==

获取随机字符

[root@fan ~]# openssl rand -base64 6
fb7cqvab
[root@fan ~]# openssl rand -base64 9
9sUSeGKEoEFD

获取8位随机数字

[root@fan ~]# openssl rand -base64 8 |cksum |cut -c 1-8
86343899

3、date

[root@fan ~]# date +%s%N
1563045292290688359
[root@fan ~]# date +%s
1563045298
[root@fan ~]# date +%N
294467639
[root@fan ~]# date +%N |cut -c 1-8
76014224

4、/dev/urandom

[root@fan ~]#  head /dev/urandom | cksum
1981767266 3484

5、计算机生成的uuid码产生随机字符

[root@fan ~]# cat /proc/sys/kernel/random/uuid
2acc0f46-a09c-4f3f-be77-2fce60ba5cde
[root@fan ~]# cat /proc/sys/kernel/random/uuid |cut -c 1-8 
d852b731

6、安装软件expect，然后使用命令mkpasswd生成随机字符

[root@localhost ~]# yum -y install expect

[root@localhost ~]# mkpasswd -l 8

6cvHu1P_

[root@localhost ~]# mkpasswd -l 8

g7jR3!Lt

[root@localhost ~]# mkpasswd -l 8

Y9wCwk4-

[root@localhost ~]# mkpasswd

h8{o4wVWf

[root@localhost ~]# mkpasswd

9bnI&zD4u

[root@localhost ~]# mkpasswd|md5sum

d9fabd642a8d4e260c95604bdd7d9cea  -

[root@localhost ~]# mkpasswd|md5sum

c5ddd81803a9308bcf31999c2441c5d9  -

7、产生随机密码

[root@fan ~]# pwgen  -1
lei3aeTh
[root@fan ~]# pwgen  5 -1
tu7eH
[root@fan ~]# pwgen  12 -1
lu5aeNae0eel
[root@fan ~]# pwgen  20 -1
zoh2mah2neu9neYeihok